[AGRANULOCYTOSIS CAUSED BY APALUTAMIDE : A CASE REPORT]

We report a case of agranulocytosis associated with apalutamide treatment in a patient with non-metastatic castration-resistant prostate cancer (nmCRPC). An 89-year-old man was diagnosed with prostate cancer (cT2cN0M0) four years earlier and treated with surgical castration and anti-androgen therapy. Subsequently, his PSA levels increased. Imaging studies showed no obvious metastases, and he was diagnosed with nmCRPC. Darolutamide was initiated but discontinued because of liver dysfunction, and treatment was switched to apalutamide. Forty-five days after the initiation of apalutamide, the patient presented with fatigue. Laboratory findings revealed severe neutropenia, with a neutrophil count of 54/μl, leading to a diagnosis of apalutamide-induced agranulocytosis. Apalutamide was discontinued, and granulocyte-colony stimulating factor (G-CSF) and antibiotics were administered. The neutrophil count recovered to the normal range 13 days after treatment. Clinicians should be aware of the potential risk of agranulocytosis when neutropenia develops during apalutamide therapy.